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21.
Summary The threonine operon fromEscherichia coli was cloned in plasmid pBR322, subcloned into the shuttle vector pCEM300 and the resulting recombinant plasmid was transferred intoBrevibacterium flavum andCorynebacterium glutamicum. The expression ofE. coli threonine genes in these coryneform bacteria was demonstrated by complementing thethrA andthrB mutations and by assaying homoserine dehydrogenase activity. 相似文献
22.
23.
G. -J. A. Vidugiris A. V. Gudavičius V. J. Razumas J. J. Kulys 《European biophysics journal : EBJ》1989,17(1):19-23
Surface enhanced Raman scattering (SERS) of some enzymes (alkaline phosphatase, horseradish peroxidase and lactoperoxidase) and some amino acids (tryptophan, tyrosine and phenylalanine) on silver electrodes has been studied. The spectral band intensities of certain amino acids and amino acid residues were determined by their orientation on the surface and depended on the electrode potential (E).Abbreviations SERS
surface enhanced Raman scattering
- Trp
tryptophan
- Tyr
tyrosine
- Phe
phenylalanine
- E
electrode potential
- ORC
oxidation-reduction cycle 相似文献
24.
Miroslav Pátek Jan Nešvera Jitka Hochmannová 《Applied microbiology and biotechnology》1989,31(1):65-69
Summary Four hybrid plasmids were constructed from the cryptic plasmid pAM330 (from Brevibacterium lactofermentum; 4.5 kb) and the broadhost-range plasmid pGV1106 (9.0 kb; Kmr Smr) isolated from Escherichia coli. All of them were mobilized from E. coli into the Gram-negative methylotrophic bacterium Methylobacillus sp. and two of these constructs (pCEM300 and pCEM400) were transferred by transformation into B. flavum and Corynebacterium glutamicum. Their kanamycin-resistance determinant coming from Gram-negative hosts was expressed in these Gram-positive bacteria. Both pCEM300 and pCEM400 are very stably maintained in B. flavum and represent suitable vectors for gene cloning in coryneform producers of amino acids. 相似文献
25.
S. Živanović 《Human Evolution》1988,3(5):329-334
Studies of the morphological features of the temporal region of mesolithic skulls from Padina in the Iron Gate Gorge of the
Danube revealed a very prominent and large supramastoid ridge which is the most striking feature in skulls of both sexes.
Mastoid processes were larger in male skulls, but in 25% of the cases there was an overlap between the size of the processes
in male and female specimens. The mastoid ridge was prominent in both sexes. The digastric fossa was always well defined in
both sexes and in the two thirds of the skull specimens it was deep. The posterior root of the zygoma was prominent in all
the skulls, but it was better developed in the male specimens. The parietotemporal suture in both sexes rises above the level
of the pterion. There were no morphological or anthropometrical differences between the left and the right side of individual
skulls outside the limits of natural asymmetry. All these morphological characteristics of the temporal region may help in
racial and sexual diagnosis of the Mesolithic skulls from the Iron Gate Gorge. 相似文献
26.
Summary Immobilization of Escherichia alcalescens cells into genu-carrageenan gel for L-aspartic acid production was studied with respect to the optimized preparation of heterogenous biocatalyst /2.5–3.0% genu-carrageenan, 15% biomass, 50–55 °C, tannin added/. 相似文献
27.
František Krahulec 《Folia Geobotanica》1988,23(2):173-179
The present paper gives comments on the nomenclature of associations ofNardetalia andNardo-Caricion rigidae from Central Europe. A brief list of important homonyms and ambiguous names is added. 相似文献
28.
The fractionation of eukaryotic DNA by field inversion gel electrophoresis results in the appearance of discrete DNA-fragments. The set of these fragments is similar to that of different eukaryotic representatives and consists of various chromosomal DNAs, unified by size. The physical properties of DNA-fragments suggest that they can form multimeric structures due to the presence of sticky ends flanking discrete fragments. We suppose that the set of discrete DNA-fragments results in a specific cleavage of intact nuclear DNA and can reflect different levels of chromatin structural organization. 相似文献
29.
Zbyněk Roček 《Pal?ontologische Zeitschrift》1991,65(3-4):351-361
Three-dimensionally preserved and chemically prepared skulls and natural casts of representatives of the families Benthosuchidae, Melosauridae, and Capitosauridae yield data on the structure of the ethmoidal endocranium, i. e. of those nasal cranial structures that consisted originally of cartilage. This study demonstrates that the ethmoidal endocranium was principally a dorsoventrally compressed plate, pierced by a broad and oblique canal which communicated anteriorly with the outer dorsal surface by the fenestra endonarina and posteriorly with the mouth cavity by the fenestra endochoanalis(seu foris). The canal was very short, and housed the olfactory organ. The ethmoidal endocranium was connected with the palatoquadrate by the commissura quadratocranialis anterior; there was no lateral ethmoidal commissure, however, in older individuals the anterior section of the palatoquadrate might also contact the postchoanal part of the nasal endocranial skeleton. 相似文献
30.
J. Nešvera M. Pátek J. Hochmannová E. Chibisova I. Serebrijski Y. Tsygankov A. Netrusov 《Applied microbiology and biotechnology》1991,35(6):777-780
Summary
Brevibacterium methylicum is a newly isolated Gram-positive facultatively methylotrophic bacterium that uses the NAD+-dependent methanol dehydrogenase for methanol oxidation and assimilates its carbon via the ribulose monophosphate cycle. Protoplasts prepared by lysozyme treatment of B. methylicum cells grown in the presence of glycine were transformed by plasmid shuttle vectors pCEM500 (16.5 kb; Smr/Spr, Kmr/Gmr) and pEC71 (7.1 kb; Kmr/Nmr) constructed on the basis of B. lactofermentum plasmid pAM330 and replicating in Escherichia coli and in amino-acid-producing coryneform bacteria. The resistance markers were found to be expressed in B. methylicum and autonomous plasmid DNAs of various size were isolated from the transformants. The presence of the pAM330 replicon in these plasmids was demonstrated by DNA-DNA hybridization experiments.
Offprint requests to: J. Nevera 相似文献